Smash Mouth was formed in 1994 when Steve Harwell, who had formerly played in a rap group called F.O.S., along with his manager, decided to form a rock band. Harwell's manager, Kevin Coleman, knew guitarist Greg Camp and bassist Paul De Lisle, who had both played in a local punk band, and introduced the three musicians to each other. They began rehearsing together, along with Kevin Coleman as drummer. They soon developed into a band, and named themselves Smashmouth, a football term. During their early years, the band played largely ska punk music. The band's first publicity came when a demo of the song "Nervous in the Alley" was played by a San José radio station, KOME. Soon after, Interscope Records signed the band, and the group's debut album, Fush Yu Mang, was released in 1997.[2] Also, upon signing to Interscope Records, the band changed their name from Smashmouth to Smash Mouth.

The band's second album, Astro Lounge, was released in 1999 and marked a change in direction, as it had less of the previous ska influence and more of a pop sound. It led to more publicity for the band, and ended up being one of the most critically acclaimed albums from the group. Supported by the single "All Star," which was featured in several movie soundtracks, Astro Lounge was eventually certified as triple platinum.[2]

Also in 1999, The East Bay Sessions was released as a collection of early songs. Shortly after the release of the album, drummer Kevin Coleman left the band due to back problems. He was initially replaced by Michael Urbano, who was quickly replaced by Mitch Marine for the tour supporting Astro Lounge, who was subsequently replaced by Michael Urbano at the conclusion of the tour.[3]

In 2001, Smash Mouth covered the Monkees' hit song "I'm a Believer".[4] It was featured on both the Shrek (along with All Star) movie soundtrack and the eponymous album Smash Mouth.[3] The album sold fewer copies than the band's earlier works, eventually being certified gold.[2] In 2001 Smash Mouth appeared as themselves in the climactic scene of the film Rat Race.

Two years after Smash Mouth was released, Get the Picture? was released, featuring the single, "You Are My Number One", "Hang On" and "Always Gets Her Way". Smash Mouth was dropped from Interscope shortly after the release of Get the Picture?. That same year, the band performed a cover of the Sherman Brothers song "I Wanna Be Like You" for the animated film The Jungle Book 2.

Following the band's signing to Universal Records, Smash Mouth released the greatest hits compilation All Star Smash Hits in 2005. The album contains some more popular songs from previous Smash Mouth albums, as well as songs from soundtrack albums which were not on the band's own releases. On certain networks and timeslots, the album was advertised as having 18 tracks, including an edited version of "Flo" and "Beer Goggles". Smash Mouth played at Gumby's Birthday Celebration in August 2005.

In December 2005, the band released a Christmas album Gift of Rock. It featured covers of Christmas songs by many artists, such as the Kinks and the Ramones, and one original song, "Baggage Claim".

Smash Mouth's fifth studio album, originally to be titled Old Habits, was expected to be released in early 2006. The band had said that the album was much more like the ska punk featured on Fush Yu Mang and The East Bay Sessions. In September 2005, the band performed what was tentatively going to be the album's first single, "Getaway Car", on Last Call with Carson Daly. The album was delayed many times, in the hope of gaining publicity with Harwell's appearance on the reality show The Surreal Life. Smash Mouth returned to the studio intent on improving the record.[5]Old Habits was shelved, replaced by Summer Girl, which included some remixed Old Habits tracks as well as new songs. After being delayed in much the same way Old Habits was for several months, the album was released on September 19, 2006. Smash Mouth let Sony Pictures use much of their music from Summer Girl and other songs for the movie Zoom, whose opening titles credit the film's music to the band.

Before the release of Summer Girl, drummer Michael Urbano left the band without warning on February 14, 2006 due to creative differences. He was initially replaced by former drummer Mitch Marine, and then by Jason Sutter, best known for his work with American Hi-Fi and the Rembrandts. The band released their new album, Summer Girl, later that year. In early 2007, one year after joining the band, Sutter left Smash Mouth to play drums for former Soundgarden and Audioslave frontman Chris Cornell; fill-in drummer Marine returned to Smash Mouth.

Greg Camp left the band in the summer of 2008. Smash Mouth recruited Leroy Miller to play guitar. Leroy left in 2009 and Camp returned to the band, but in 2011 Camp left once again and this time the band recruited Sean Hurwitz. Hurwitz stayed until 2012, and was replaced by Mike Krompass. Later in 2012, Hurwitz returned. In 2009 Mitch Marine left once again and was replaced by Urbano, who left again after only one year in 2010, and was replaced by Marine once again. Marine left yet again after a brief spell in 2010 and was replaced by Randy Cooke. Cooke was briefly replaced by Jason Sutter in 2011, then Charlie Paxson.

After parting ways with Universal Records and signing with 429 Records, Smash Mouth released their sixth studio album titled Magic, on September 4, 2012. The album was primarily produced by new band member Mike Krompass. The first single, also entitled "Magic", debuted on the Billboard Adult Contemporary chart at No. 22.[6] The band spent the rest of 2012 touring behind the new project as well as promoting the release of their rock and roll cookbook — Recipes from the Road.[7] Cooke left permanently toward the end of 2012, replaced by Paxson. Paxson left in July 2013 during the Under the Sun tour, and was initially going to be replaced by a returning Cooke; however, he was replaced by Sutter once again. Tod Burr, former drum tech of Def Leppard and drummer of Merle Jagger, came on board in 2012 as drum and keyboard tech of Smash Mouth.

On February 1, 2013, Smash Mouth headlined[8] the AutoNation Coast to Coast rebranding event (which combined all AutoNation dealerships into a single brand) at Wayne Huizenga Park in Fort Lauderdale, FL with Michela Paige from Season 3 of The Voice. The event also served as a final round in the AutoNation Culture of Caring Contest.